Three Months Ended March 31, | Year Ended December 31 | |||||||||||||||||||||||
| 2012 | 2011 | 2010 | 2009 | 2008 | 2007 | |||||||||||||||||||
| Earnings, as defined: | ||||||||||||||||||||||||
| Pretax income from operations | $ | 17,790 | $ | 145,034 | $ | 126,933 | $ | 108,245 | $ | 52,769 | $ | 55,596 | ||||||||||||
Add: Fixed charges | 25,417 | 100,901 | 100,518 | 114,684 | 74,525 | 57,247 | ||||||||||||||||||
Total earnings, as defined | $ | 43,207 | $ | 245,935 | $ | 227,451 | $ | 222,929 | $ | 127,294 | $ | 112,843 | ||||||||||||
| Fixed charges, as defined: | ||||||||||||||||||||||||
Interest charges | $ | 16,706 | $ | 65,095 | $ | 63,912 | $ | 71,688 | $ | 61,090 | $ | 55,261 | ||||||||||||
Interest component of leases | 8,711 | 35,806 | 36,606 | 42,996 | 13,435 | 1,986 | ||||||||||||||||||
Total fixed charges, as defined | $ | 25,417 | $ | 100,901 | $ | 100,518 | $ | 114,684 | $ | 74,525 | $ | 57,247 | ||||||||||||
| Ratio of earnings to fixed charges | 1.7 | 2.4 | 2.3 | 1.9 | 1.7 | 2.0 | ||||||||||||||||||
